PaperCut NG/MF Missing Authentication for Critical Function Vulnerability

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

• cpe papercut/papercut mfversion unspecified
• cpe papercut/papercut ngversion unspecified
• vendor PaperCut NG/MFversion unspecified

How to fix CVE-2026-81578

• Recommended remediation

  Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines. CISA due date Sep 14, 2026.

• Official advisories

  • CISA KEV · cisa.gov
  • CVE.org · cve.org
  • FIRST EPSS · first.org
  • Nuclei Templates · github.com
  • NIST NVD · nvd.nist.gov
  • Rapid7 Vulnerability Database · rapid7.com

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Code

The project this record applies to. Exploit listings stay in References.

• Repository · github.com

Timeline

Detection, updates, and resolution for this record.

1. Aug 28, 2026 · Catalog

   Detected

   An improper access control vulnerability exists in the web management interface of PaperCut MF and PaperCut NG. Under specific conditions, unauthenticated remote requests targeting administrative functions can trigger backend actions prior to the completion of access validation checks. This allows an unauthenticated remote attacker to modify certain system configurations.

2. Aug 31, 2026 · CISA KEV

   Known exploited

   Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating

3. Sep 13, 2026 · Catalog

   Updated

   An improper access control vulnerability exists in the web management interface of PaperCut MF and PaperCut NG. Under specific conditions, unauthenticated remote requests targeting administrative functions can trigger backend actions prior to the completion of access validation checks. This allows an unauthenticated remote attacker to modify certain system configurations.

4. Sep 14, 2026 · CISA KEV

   Remediation due

   Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating

Sources

• CISA KEVConfirmed exploitationCVE-2026-81578

  PaperCut NG/MF contains a missing authentication for critical function vulnerability which allows an unauthenticated remote attacker to modify certain system configurations. This vulnerability can be chained with CVE-2026-82078.

  cisa.gov
• CVE.orgVulnerability recordCVE-2026-81578

  Official CVE identifier

  cve.org
• FIRST EPSSExploitation probabilityCVE-2026-81578

  30-day exploitation probability 85.6%

  first.org
• Metasploit ModulesPublic exploit moduleexploit_multi/http/papercut_ng_external_user_lookup_rce

  Public module reference (excellent). Module source is not copied into this catalog.

  rapid7.com
• Nuclei TemplatesDetection templateCVE-2026-81578

  CVE-2026-81578 has a public Nuclei detection template.

  github.com
• NIST NVDVulnerability recordCVE-2026-81578

  An improper access control vulnerability exists in the web management interface of PaperCut MF and PaperCut NG. Under specific conditions, unauthenticated remote requests targeting administrative functions can trigger backend actions prior to the completion of access validation

  nvd.nist.gov
• Rapid7 Vulnerability DatabaseResearchCVE-2026-81578

  Overview On August 27, 2026, PaperCut Software published an urgent security advisory stating that it is investigating active exploitation of a vulnerability affecting PaperCut NG and PaperCut MF. PaperCut has confirmed customer incidents and is treating the issue as a security emergency. At the initial time of disclosure, the vulnerability had not been assigned a CVE identifier, and PaperCut had n

  rapid7.com
• VulnCheck KEVConfirmed exploitationCVE-2026-81578

  PaperCut NG/MF contains a missing authentication for critical function vulnerability which allows an unauthenticated remote attacker to modify certain system configurations. This vulnerability can be chained with CVE-2026-82078.

  vulncheck.com

References

• VulnCheck exploitation evidence · euvd.enisa.europa.eu
• Issue Tracking · github.com
• CISA note · nvd.nist.gov
• VulnCheck exploitation evidence · previdian.com
• Patch · cisa.gov
• CISA note · cisa.gov
• CISA note · cisa.gov
• VulnCheck exploitation evidence · huntress.com
• VulnCheck exploitation evidence · linkedin.com
• CISA note · papercut.com
• VulnCheck exploitation evidence · x.com

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.